/*
  Copyright (c) 2011 Arduino.  All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include "wiring_pulse.h"

/* Measures the length (in microseconds) of a pulse on the pin; state is HIGH
 * or LOW, the type of pulse to measure.  Works on pulses from 2-3 microseconds
 * to 3 minutes in length, but must be called at least a few dozen microseconds
 * before the start of the pulse.
 *
 * ATTENTION:
 * This function relies on micros() so cannot be used in noInterrupt() context
 */
uint32_t pulseIn(uint32_t pin, uint32_t state)
{
    // Cache the port and bit of the pin in order to speed up the
    // pulse width measuring loop and achieve finer resolution.
    // Calling digitalRead() instead yields much coarser resolution.
    uint32_t timeout = 1000000L;
    pinMode(pin, INPUT);
    uint32_t startMicros = micros();

    // wait for any previous pulse to end
    while (gpio_input_bit_get(digitalPinToPort(pin), digitalPinToBit(pin))) {
        if (micros() - startMicros > timeout) {
            return 0;
        }
    }

    // wait for the pulse to start
    while (!gpio_input_bit_get(digitalPinToPort(pin), digitalPinToBit(pin))) {
        if (micros() - startMicros > timeout) {
            return 0;
        }
    }

    uint32_t start = micros();
    // wait for the pulse to stop
    while (gpio_input_bit_get(digitalPinToPort(pin), digitalPinToBit(pin))) {
        if (micros() - startMicros > timeout) {
            return 0;
        }
    }
    return (micros() - start);
}

uint32_t pulseInLong(uint32_t pin, uint32_t state)
{
    return pulseIn(pin, state);
}